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As consumers, we’re more like sheep than we’d like to admit – that is, if sheep were tempted to buy food based on “free from” marketing. Gluten-free, fat-free, lactose-free, dairy-free and GMO-free labels are already firmly stamped on many of the foods we buy in shops and restaurants, and are associated with an invisible yet potent, virtuous halo. After all, if a slice of cake is gluten-free, it must be positively healthy.

The latest marketing wheeze appears to be “slaughter-free” dairy production – a 30 cow herd in Rutland, described as a bovine spiritual utopia, where calves are not weaned but run with cows as “grazing partners”; male calves (renamed as ”oxen”) are used for draught power rather than reared as beef; and once cows retire from milking, they are literally put out to pasture rather than being culled.

There’s no doubt that this ticks an entire list of ethical boxes – who doesn’t want to imagine that cows live a happy life browsing the buttercups once they’re too old to produce milk? Yet, given the critical need to produce food sustainably (in terms of economic viability, environmental responsibility and social acceptability), it also leads to a number of questions.

While there may well be a niche market of consumers who are prepared to pay £4.50 per litre for slaughter-free milk; in an era when we primarily choose foods based on price, is this endeavour going to achieve long-term economic sustainability?

In a system where no cattle are slaughtered, but where cows need to have a calf on a regular basis to produce milk, the herd size will increase exponentially over time. In two, five or ten years time, how will the owners reconcile philosophical arguments against slaughter with the difficulty of supplying enough feed to fulfil the requirements of an ever-expanding herd using a fixed quantity of pasture?

Finally, and most importantly, animal welfare should be the cornerstone of any dairy farm. Euthanasia is upsetting, yet is the only option when animals are too sick or injured to survive. As consumers, we need to take responsibility for the fact that slaughter of both healthy animals (for meat) and sick animals (for humane reasons) is an unavoidable, if unpalatable truth. Just as the recent ban on cattle slaughter for beef in India is going to have negative impacts on food security, economic sustainability and environmental impacts, it’s time that we faced up to the reality of food production and stop thinking that we can have our slaughter-free dairy and eat it!

Unlike most of my media interviews, which are focus entirely on sustainability and have me spouting numbers like data is going out of fashion; this was a huge amount of fun and Will got me admitting to a celebrity crush, the fact that I have to put bacon and cheese on hot cross buns and the fact that, as an undergrad, I was so useless at presentations that even the lecturers felt sorry for me.

So if you fancy listening to a fabulous Welsh accent (Will) and a slightly overexcited Oxford/Shropshire/Montana-hybrid (me) discussing the best types of cheese, beating cancer at 25 and the perils of being a reformed vegan in addition to the best way to ensure future livestock sustainability (hint: there’s no one-size-fits-all), check it out here.

Commercial dairy cows in Cumbria – should they be “retired” before slaughter?

Good grief. Just when I think I’ve heard it all, another food pundit comes up with an idea so daft that you could bottle it and sell it as vegan, gluten-free, dairy-free, humanely-reared organic water. The latest brainwave from Jamie Oliver is to “retire” old dairy cows onto pasture, where they can graze for four years before producing highly-marbled beef. Contrary to most of the breed-related marketing, Holstein beef is pretty good, so it’s a mouth-watering concept until we take a step back and think about the actual sustainability impacts.

Producing beef from cull dairy cattle? Excellent idea. I once had a heated argument with an activist protestor outside the Smithsonian Museum in Washington DC who seemed surprised that, when he told me that most cull dairy cows end up as burgers, I didn’t renounce my heathen ways and immediately seek out the nearest tofu burrito. It makes perfect sense – where would be the logic in discarding an entire cow’s worth (~301 kg) of nutritious, delicious beef simply to bury, burn or use the meat for non-food purposes? Indeed, ~50% of the UK (and ~24% of the US) beef supply comes either from cull dairy cows or dairy calves reared for beef.

Is there an argument for giving extra feed to cows that are going to be culled so that they get a little fatter and produce tastier beef? Yes indeed, adding value to cull dairy cows is a great idea, especially when the beef price is high. But here’s the rub. The average dairy cow in the U.K. is culled at 6.4 years of age. By that time she should have reached her mature weight, which means that the majority of extra weight she puts on in “retirement” is fat. Although we love the streaks of intramuscular fat that we see in a steak (marbling) and enjoy the depth of flavour that gives to the meat, the vast majority of fat on a carcass isn’t particularly edible. So we’re feeding a cow for four years of retirement in order to discard (or rather render into tallow – perhaps to make some £5 notes?) a significant proportion of the weight that she gains.

A cow will eat 2-2.5% of her body weight in dry matter every single day. Four years of feeding a 700 kg cow = 4 x 365 days x 700 kg x 0.025 = 25,550 kg of feed dry matter, or 106,458 kg of fresh grass given that it’s only ~24% dry matter. Plus 4-years worth of drinking water, manure and greenhouse gas (GHG) emissions. A hefty environmental impact compared, for example, to rearing two beef steers on the same amount of pasture over a 4-year period, in addition to culling the dairy cow when she leaves the herd (sans retirement). That scenario would provide 200% more beef (~900 kg total, even allowing for the lighter weight for grass-finished vs. grain-fed steers) from the same amount of pasture and with a smaller total quantity of manure and GHG emissions because the growing animals are lighter in weight throughout, therefore excrete and emit less*.

I can’t decide whether the increasingly asinine proposals for sustainable food production propounded by Jamie Oliver’s “Friday Night Feast” programme, which recently left the casual viewer with the impression that welfare of housed dairy cows is equivalent to that of battery hens are serious, or simply a way to court fame through controversy. However, the number of tweets lauding the programme’s food philosophy is alarming given the amount of time devoted to non-sustainable ideology. Time for TV programmers to redress the balance with some Friday Night Facts vs. Fiction?

*Note that I have not accounted for the beef cows needed to produce the steers, nor for the cost of rearing the dairy cow or the heifer needed to replace her in dairy herd. This is not a full system assessment, but simply about the best use of a unit of pasture area – adding fat to a mature cow (less efficient) or adding muscle and fat to growing animals (more efficient)

Every food has an environmental impact, whether it’s cheeseburgers or tofu, coffee or corn.

That shouldn’t come as a surprise to any of us and, as a scientist, sustainability consultant and parent, I don’t have a problem with food production being one of the biggest contributors to global environmental impacts. Why? Because food production is one of the few industries that are absolutely essential for human life. However, it’s clear that we need to take steps to reduce environmental impacts from human activity, and as such, the livestock industry is often criticised for both resource use and greenhouse gas (GHG) emissions.

Although meat production is predicted to increase from now until at least 2050, it should be noted that the trends for improved productivity and efficiency within global livestock industries also reduce environmental impacts. As described in Marian Swain’s essay on meat production, the US beef industry cut resource use and greenhouse emissions considerably between 1977 and 2007. Meanwhile, the rise of modern feedlot-finishing systems cuts land use, water use, and emissions per unit of beef compared to grass-finished meat.

These findings may seem intuitively incorrect as we’re constantly exposed to marketing and media messages suggesting that only grass-fed meats are environmentally sustainable, and that intensive livestock systems are undesirable. The data speak for themselves however—the majority of extensive systems finish cattle at lighter weights (thus requiring more total animals to maintain beef supply), have lower growth rates (so cattle take longer to grow to their finish weight) and often have lower reproductive performance in female cattle.

All these factors combine to increase environmental impacts. But when I presented this data to a group of French Masters-level Livestock Engineering students earlier this month, they were (in their own words) shocked. Even among experts and students, there remains a great deal of misunderstandings when it comes to meat production.

Does this mean that every beef producer worldwide should embrace feedlot-finishing and reduce pasture use? Absolutely not. One of the major benefits of cattle compared to swine and poultry is that they digest and use human-inedible forages, such that dairy and grass-fed beef cattle actually produce more human-edible protein in the form of milk and meat than they consume; and feedlot-finished beef cattle have a ratio of human-edible feed intake to human-edible protein output similar to that of swine, despite their greater overall land use. In keeping with the themes discussed in the Swain’s essay, there is no magic bullet—it is essential to fit production systems to the cattle, climate, market, and culture within each region and to improve productivity within each and every system.

So rather than reducing animal protein consumption as we move towards 2050, we might ponder keeping total consumption relatively stable, with a more equitable distribution across the globe? This would allow for a decrease in over-consumption in high-income regions, while providing a greater quantity of milk, meat, and eggs to those who have dire need for adequate animal proteins to maintain health and to promote adequate child growth and development. While the environmental impact of beef production is a key concern, we also have to examine the role of livestock in economic and social sustainability. For billions of small-scale farmers, cattle provideeconomic viability, improved nutrition, social status and a means to diversify agricultural production as well as tangible benefits in terms of fertilizer, hides and other by-products.

Should we insist that global beef production is abandoned in favour of increased legumes, nuts or lab-created proteins? No. We simply need to give producers worldwide the education, tools and technologies to make the best and most efficient use of their resources. Only then will we have a truly sustainable (environmentally responsible, economically viable and socially acceptable) global meat industry.

For those of us in the UK, mentioning Danish livestock production almost inevitably leads to thoughts of Danish bacon (be still my beating heart) – a considerable proportion of their 90% of domestic pork products that are exported. However, any beef lovers in Denmark may be in trouble, as recent news articles suggest that red meat (beginning with beef) will soon be taxed in order to cut consumption and meet greenhouse gas targets.

Despite the number of voices clamouring for reduced meat consumption, it seems clear that the average consumer isn’t going to forgo meat and dairy simply because a new study is publicised in the lay press. I’m firmly of the opinion that the only way that meat consumption will decline is if it becomes too expensive to include in the weekly shopping basket. Indeed, although meat consumption per capita has declined in the USA over the past 10 years, demand (as measured by the price that the consumer is willing to pay) has increased over recent years.

So will taxing meat lead to a reduction in consumption? For those who routinely order a 16 oz (454 g) steak in a restaurant or think nothing of tucking into a chateaubriand, probably not. High end cuts of beef are associated with celebrations and luxury dining, and going out for a broccoli pasta bake just doesn’t have that same ring to it.

However, we live in a world where 793 million people (10.7 % of the global population) are undernourished – and that isn’t simply confined to people in developing regions. That means that almost 1 in 9 people do not have enough food. To low-income consumers, food availability isn’t simply a function of what is on the shelf in the supermarket, it’s directly related to economic cost and convenience. If red meat is taxed, it will still be eaten, but there will be a disproportionate shift towards consumers with a greater income and away from those who are in most need of affordable high-quality protein, including growing children.

Do beef alternatives exist? Absolutely – protein can be supplied from other meats, fish or vegetable-based foods. Yet here’s where the convenience aspect comes in – most of us can probably think of a quick and easy recipe involving beef, but how many can you think of involving tofu or lentils? That’s not to say that we shouldn’t expand our cooking repertoires, but when time is at a premium, quick easy recipes that will feed a family win every time.

Greenhouse gases are important, but they are not the only factor that we should consider when advocating for sustainable dietary choices. In a world where millions of people are food-insecure, removing a protein choice from the table of those with low incomes simply adds to the problem of how to feed the world – sustainably.

It is equally interesting, inevitable and lamentable to see that another study has come out claiming that the only way to reduce climate change is to cut meat consumption per person.

Meat consumption appears to be the only human activity subject to continuous “we must cease/reduce this” claims on the basis of environmental impacts. If we compare to other greenhouse gas sources, a considerable proportion come from transportation. Yet rather than insisting that every car-owner cut their annual mileage by 25%, the focus has been on reducing emissions by producing more fuel-efficient vehicles. Similarly, no one has yet claimed that we should reduce household lighting by four hours per day, but the compact fluorescent lightbulb (CFL) has become the poster child for improving household energy efficiency.

We have demonstrable proof that beef and dairy producers have improved greenhouse gas emissions (as well as land use, water use, energy efficiency, etc) over time through improved efficiency, and can continue to do so into the future. So why are the gains made by livestock producers dismissed, and reduced meat intakes seen as the only solution? I have an absolute hatred of conspiracy theories, but it is difficult not to see an latent agenda in the preponderance of “Cut meat consumption” papers. Jumping on the bandwagon? Promoting individual dietary opinions as science? Or simply bowing to NGO/media opinions and looking for easy funding and publicity?

As the global population increases to over 9.5 billion people by 2050, with the majority of this growth occurring in the developing world, the demand for milk, meat and eggs is going to increase by 60%. If we are serious about cutting greenhouse gas emissions, it’s time to examine the impacts of all of our actions and concentrate on further efficiency improvements rather than constraining dietary choice.

Media articles relating to agriculture appear to fall into two groups. Those relating to small-scale agriculture are glowing accounts of farmers wearing overalls and straw hats; lovingly taking care of the land and animals according to holistic principles; and selling their produce at the local farmers’ market. By contrast, commentary upon large-scale agriculture invokes images of corporate-controlled factory farms with blatant disregard for animal welfare and local community issues; blithely pumping animal manure into water courses.

To use the U.S. dairy industry as an example: over three-quarters (76.7%) of dairy farms have small herds (less than 100 cows) and only 4.2% are large, with more than 500 cows in the herd. Yet the contribution to total milk supply is disproportionate – those 76.7% of herds containing <100 cows produce only 13.7% of U.S. milk, whereas the 4.2% of farms with >500 cows produce 63.0% of U.S. milk. A 17% increase in milk yield per cow is exhibited in large herds compared to small herds – does this mean that so-called mega farms are more efficient? Yes. They have a higher output of milk per unit of input. Data from the FAO also shows that as milk yield increases, the carbon footprint (and other resource use impacts) per unit of dairy is reduced.

Does this mean that large herds are better? Not necessarily. There’s no measure of animal health, worker conditions, or community support in these data. Yet these issues are size-independent. It’s possible to have poor animal health or worker conditions on a small farm, just as it is on a large farm. I’ve seen some great small operations, but also visited amazing large farms, including a 1,200 cow dairy in SE England where I was extremely impressed to see that they had a hospital pen to segregate sick cows from the rest of the herd, and that it only contained 12 cows. A 1% morbidity rate. How would that compare to the average human workplace, school or city?

Is there an ideal farm or herd size? A blueprint to lead the global dairy industry during the current crisis? No. Dairy farms vary considerably – it would be foolish to suggest that there is only one sustainable way to produce milk (although this approach is often taken by certain NGO groups). However, one thing is clear. As we approach a global population of 9.5+ billion people in 2015, we need to stop vilifying large farms and worshipping small farms, and instead promote efficient, well-managed, productive farms that can survive the crisis, regardless of size. As the saying goes – it’s not size that matters, it’s what you do with it that counts.

Food transportation. It’s the curse of the modern world. Just think how much brighter and sunnier the planet would be if we all shopped locally, tootling along on our bicycles to pick up freshly-baked bread and a dozen eggs just as our grandparents would have done. A brave new world unemcumbered by gas pumps and trucks. Except…. Well, no. It’s not that simple.

In many cases, transport is a tiny proportion of total greenhouse gas emissions per unit of food – for example, it’s less than 1% of the carbon footprint of one lb of beef. However, food miles are often cited as an environmental proxy to differentiate between food choices, the assumption being that an egg which travels 2,000 miles across the country is less environmentally-friendly than one produced in the next county. Indeed, one farm website proclaims that “We do not ship anything anywhere. We encourage folks to find their local producers and patronise them”, while on the same page, a customer testimonial proudly proclaims: “I drive to <Farm X> 150 miles one-way in order to buy clean meat for my family”.

Given the dichotomy between these two statements, let’s compare buying eggs from a grocery store with a local farm (full analysis here). Food miles are far greater for eggs that have traveled from Texas to Virginia to be sold in the grocery store (2,405 miles round-trip), compared to driving to the local farm (300 miles round-trip); and the fuel efficiency is far worse for a truck (5.4 mpg) than a car (22.6 mpg); yet a modern truck can carry 23,400 dozen eggs.

Unless your car is packed to the roof with eggs, traveling to the farm to buy them emits 55X more greenhouse gas emissions than driving to the store to buy them. Bottom line? Unless the local farm is closer than the store, or you’re able to walk/cycle there*, it’s more environmentally-friendly to buy eggs from the store, because the greenhouse gas emissions attributable to one dozen eggs out of 23,400 dozen is a tiny fraction of the total.

One report claims that greenhouse gas emissions from one large container ship is equivalent to 50 million cars – however, in this instance it’s the result of sulphur dioxide emissions from poor quality shipping fuel rather than inefficiency. Mass transport may not have a feel-good factor associated with driving out to a farm, but it allows us to enjoy a wide variety of affordable foods with a low carbon footprint – essential factors for a sustainable food future.